nes-proj/core/net/mac/framer-nullmac.c
Niclas Finne 68730566a3 Added method to framer that returns the header length if the framer
would create a header with the current packet information.

This allows sicslowpan to calculate the max payload size without
consuming a sequence number or clearing/restoring the packet buffer.
2014-04-11 17:03:23 +02:00

102 lines
3.6 KiB
C

/*
* Copyright (c) 2009, Swedish Institute of Computer Science.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
/**
* \file
* MAC framer for nullmac
* \author
* Niclas Finne <nfi@sics.se>
* Joakim Eriksson <joakime@sics.se>
*/
#include "net/mac/framer-nullmac.h"
#include "net/packetbuf.h"
#define DEBUG 0
#if DEBUG
#include <stdio.h>
#define PRINTF(...) printf(__VA_ARGS__)
#define PRINTADDR(addr) PRINTF(" %02x%02x:%02x%02x:%02x%02x:%02x%02x ", ((uint8_t *)addr)[0], ((uint8_t *)addr)[1], ((uint8_t *)addr)[2], ((uint8_t *)addr)[3], ((uint8_t *)addr)[4], ((uint8_t *)addr)[5], ((uint8_t *)addr)[6], ((uint8_t *)addr)[7])
#else
#define PRINTF(...)
#define PRINTADDR(addr)
#endif
struct nullmac_hdr {
linkaddr_t receiver;
linkaddr_t sender;
};
/*---------------------------------------------------------------------------*/
static int
hdr_length(void)
{
return sizeof(struct nullmac_hdr);
}
/*---------------------------------------------------------------------------*/
static int
create(void)
{
struct nullmac_hdr *hdr;
if(packetbuf_hdralloc(sizeof(struct nullmac_hdr))) {
hdr = packetbuf_hdrptr();
linkaddr_copy(&(hdr->sender), &linkaddr_node_addr);
linkaddr_copy(&(hdr->receiver), packetbuf_addr(PACKETBUF_ADDR_RECEIVER));
return sizeof(struct nullmac_hdr);
}
PRINTF("PNULLMAC-UT: too large header: %u\n", sizeof(struct nullmac_hdr));
return FRAMER_FAILED;
}
/*---------------------------------------------------------------------------*/
static int
parse(void)
{
struct nullmac_hdr *hdr;
hdr = packetbuf_dataptr();
if(packetbuf_hdrreduce(sizeof(struct nullmac_hdr))) {
packetbuf_set_addr(PACKETBUF_ADDR_SENDER, &(hdr->sender));
packetbuf_set_addr(PACKETBUF_ADDR_RECEIVER, &(hdr->receiver));
PRINTF("PNULLMAC-IN: ");
PRINTADDR(packetbuf_addr(PACKETBUF_ADDR_SENDER));
PRINTADDR(packetbuf_addr(PACKETBUF_ADDR_RECEIVER));
PRINTF("%u (%u)\n", packetbuf_datalen(), sizeof(struct nullmac_hdr));
return sizeof(struct nullmac_hdr);
}
return FRAMER_FAILED;
}
/*---------------------------------------------------------------------------*/
const struct framer framer_nullmac = {
hdr_length, create, parse
};